An increasing number and variety of electronic devices are powered via rechargeable batteries. Such devices include mobile phones, portable music players, laptop computers, tablet computers, computer peripheral devices, communication devices (e.g., BLUETOOTH devices), digital cameras, hearing aids, and the like. While battery technology has improved, battery-powered electronic devices increasingly require and consume greater amounts of power, thereby often requiring recharging. Rechargeable devices are often charged via wired connections that require cables or other similar connectors that are physically connected to a power supply. Cables and similar connectors may sometimes be inconvenient or cumbersome and have other drawbacks. Wireless power charging systems, for example, may allow users to charge and/or power electronic devices without physical, electrical connections, thus reducing the number of components required for operation of the electronic devices and simplifying the use of the electronic device. As such, wireless charging systems and methods that efficiently and safely transfer power for charging rechargeable electronic devices are desirable. Wireless power transfer systems include a power transmitting unit (e.g., a charging device or transmitter) and one or more power receiving units (e.g., a cellphone, a laptop, etc.) to be charged. The receiving units may be used to provide power to hardware and circuitry coupled to the receiving units. The power level transmitted by a transmitting unit may be adjusted to advantageously provide a preferred or sufficient power to the receiving units. The transmit power level may need to be readjusted upon the detection of configurations of various receiving units.